Friend showed me this; Thought I'd share.
Here's how he did the brain thing btw;
1. "Images come off the scanner in DICOM (.dcm) format; I use dcm2nii to convert to NIfTI (.nii) format;
2. ITKSnap can read .nii and write .stl meshes. Blender reads .stl!
3. The clean up is where the most work is needed, but removing doubles and smoothing vertices go a long way. Best of all, all of these softwares are free!"
I didn't figure this out. A redditer did. I plan on trying it out. Now I just need to figure out where I can get my head scanned for cheap. >_>